Plural shaft electrode support for fusing machine

ABSTRACT

A fusing machine utilizes a fusing electrode assembly and a ground electrode assembly suspended from the fusing electrode assembly. The fusing electrode assembly includes a lower fusing electrode shaft and an upper fusing electrode shaft. The lower fusing electrode shaft has an open end adapted to receive the upper fusing electrode shaft and a compression spring interposed between the shafts. An adjustable stop is threaded onto the upper fusing electrode shaft to limit the downward movement of the upper fusing electrode shaft. The lower fusing electrode shaft is keyed to a fusing electrode holder formed from a plurality of keyed members. The ground electrode assembly includes an adjusting mechanism, whereby the position of a ground electrode carried by the ground electrode assembly can be adjusted relative to a fusing electrode carried by the fusing electrode assembly. The fusing electrode assembly and the ground electrode assembly are mounted to a frame which is adjustably attached to a supporting structure.

FIELD OF THE INVENTION

The present invention relates to fusing machines, and, moreparticularly, to such machines which are especially adapted to fuse orspot weld electric motor armature wires to commutator bars. Theseapparatus generally include a pair of electrodes which constitute theterminals of a welding circuit and means for moving the electrodes intoand out of contact with the parts to be welded or fused, the fusing orwelding operation taking place at the point of contact between one ofthe electrodes and the parts to be fused or welded.

BACKGROUND OF THE INVENTION

Fusing machines have been in existence for many years. In Warner U.S.Pat. No. 3,045,103, there is disclosed a fusing machine which has beenmarketed successfully for a number of years by the assignee of thepresent invention. Despite the commercial success of the fusing machineof the Warner patent, the machine has room for improvement. Forinstance, the prior fusing machine employs a fusing electrode assembly,including a fusing electrode shaft and a pair of counteracting springs,i.e., a weld following spring for pressing a fusing electrode intocontact with a workpiece and a return spring for moving the fusingelectrode out of contact with the workpiece. Because the return springacts against the weld following spring, it is difficult to properlycompress the weld following spring, making it difficult to achieveconsistent welds. The weld following spring is also difficult toreplace, thereby increasing machine down time during spring changingoperations.

The fusing electrode assembly also utilizes a reciprocating guide pinand a reciprocating stop shaft, both of which are arranged parallel tothe fusing electrode shaft. Because of such a parallel arrangement, thefusing electrode shaft can pivot relative to the guide pin and the stopshaft and, therefore, become jammed during its reciprocating movement ina bearing bracket.

In the prior fusing machine, the fusing electrode is simply clampedbetween a pair of jaws attached to the fusing electrode shaft. Becausethe jaws are only held together by screws, the jaws can move laterallyrelative to each other, resulting in an undesired lateral movement ofthe fusing electrode. The lateral movement of the fusing electrodecomplicates its proper alignment and positioning.

The fusing electrode assembly is mounted to a main frame, including abed attached to the main frame. The bed carries an armature-commutatorholding and indexing mechanism. The bed is adjustable so that itsposition can be varied to compensate for various sized commutators.Because the position of the armature-commutator holding and indexingmechanism changes in response to the movement of the bed, differentsized commutators must be fed to the armature-commutator holding andindexing mechanism at different elevations, thereby complicating feedingoperations. If all of the commutators are fed at the same elevation,then fusing operations must be periodically interrupted to adjust theposition of the bed and, hence, the armature-commutator holding andindexing mechanism in order to receive different sized commutators andproperly position them relative to the fusing electrode and a groundelectrode.

SUMMARY OF THE INVENTION

Many of the problems and shortcomings of the prior art device describedabove are overcome by the present invention in which a fusing electrodeassembly utilizes a single spring designed to perform a weld followingfunction. The spring is positioned in an open end of a lower fusingelectrode shaft, the spring being readily accessible for easyinstallation and replacement. The lower fusing electrode shaft carries afusing electrode holder which includes a guide pin arrangedperpendicular to the lower fusing electrode shaft and designed toprevent rotation of the fusing electrode assembly about its longitudinalaxis.

The fusing electrode assembly also includes an upper fusing electrodeshaft which is mounted for reciprocating movement in the open end of thelower fusing electrode shaft, the spring being interposed between theupper fusing electrode shaft and the lower fusing electrode shaft. Theupper fusing electrode shaft carries an adjustable stop, which isarranged coaxially therewith and designed to limit the downward movementof the upper fusing electrode shaft, and a spring adjusting member,which is designed to adjust the preload compression of the spring sothat different spring requirements will not necessarily require springreplacement.

In one embodiment, the fusing electrode holder includes an upper holdingmember, which is keyed to the lower fusing electrode shaft, and a lowerholding member, which is keyed to the upper holding member and adaptedto adjustably receive the fusing electrode. The keyed connectionscooperate to rigidly support the fusing electrode, thereby facilitatingits proper alignment and positioning for the successful performance of afusing operation. The keyed connection between the upper and lowerholding members also facilitates heat transfer between the upper andlower holding members, thereby facilitating the cooling of the fusingelectrode.

A ground electrode assembly, which carries a ground electrode, issuspended from the fusing electrode assembly. The ground electrodeassembly includes an adjusting member designed to adjust the position ofthe ground electrode relative to the fusing electrode.

The fusing electrode assembly and the ground electrode assembly aremounted to a frame, which is adjustably attached to a supportingstructure. By adjusting the position of the frame, the positions of thefusing electrode and the ground electrode relative to a stationaryworkpiece work station can be adjusted without having to adjust theposition of the work station, thereby facilitating the feeding ofworkpieces to the work station.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, referencemay be had to the following description of an exemplary embodiment takenin conjunction with the accompanying figures of the drawings, in which:

FIG. 1 is a front elevational view of an exemplary embodiment of afusing head assembly constructed in accordance with the presentinvention;

FIG. 2 is a right side elevational view of the fusing head assemblyshown in FIG. 1;

FIG. 3 is a cross-sectional view, taken along line I--I in FIG. 1 andlooking in the direction of the arrows, of a fusing electrode assemblyutilized in connection with the fusing head assembly illustrated inFIGS. 1 and 2;

FIG. 4 is a cross-sectional view, taken along line II--II in FIG. 3 andlooking in the direction of the arrows, of the fusing electrode assemblyshown in FIG. 3;

FIG. 5 is a cross-sectional view, taken along line III--III in FIG. 1and looking in the direction of the arrows, of a ground electrodeassembly employed by the fusing head assembly of FIGS. 1 and 2;

FIG. 6 is a cross-sectional view, taken along line IV--IV in FIG. 1 andlooking in the direction of the arrows, of a guiding mechanism for thefusing electrode assembly of FIGS. 3 and 4;

FIG. 7 is a cross-sectional view, taken along line V--V in FIG. 1 andlooking in the direction of the arrows, of a fusing electrode springassembly utilized in connection with the fusing head assembly shown inFIGS. 1 and 2;

FIG. 8 is a cross-sectional view showing the fusing electrode springassembly of FIG. 7 in a different stage of operation from the stage ofoperation illustrated in FIG. 7;

FIG. 9 is a cross-sectional view showing the fusing electrode springassembly of FIGS. 7 and 8 in a stage of operation different from thestages of operation shown in FIGS. 7 and 8; and

FIG. 10 is a cross-sectional view, taken along line VI--VI in FIG. 1 andlooking in the direction of the arrows, of an elevating mechanism forthe fusing head assembly of FIGS. 1 and 2.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT

Referring to FIGS. 1-10, there is shown a fusing head assembly 10 havinga head support 12 which includes a fusing electrode assembly 14 and aground electrode assembly 16. The fusing electrode assembly 14 includesan upper fusing electrode shaft 18, which is slidably received in anopen chamber 20 provided in a lower fusing electrode shaft 22. The lowerfusing electrode shaft 22 is mounted for vertical reciprocating movementin an upper bearing block 24 and a lower bearing block 26.

An extensible piston rod 28 of a double-acting pneumatic cylinder 30 ispinned to the upper end of the upper fusing electrode shaft 18 forraising and lowering the fusing electrode assembly 14. The upper fusingelectrode shaft 18 carries a stop 32, which is threaded onto the upperfusing electrode shaft 18 so that the position of the stop 32 can beadjusted. The lower end of the upper fusing electrode shaft 18 carries akey 34, which rides in a slot 36 (see FIGS. 7-9) formed in the lowerfusing electrode shaft 22, and a spring adjusting member 38 forpreloading a compression spring 40 housed in the chamber 20 of the lowerfusing electrode shaft 22.

The spring adjusting member 38 has a shaft 42 threadedly received in thelower end of the upper fusing electrode shaft 18 and a contact head 44which engages the upper end of the spring 40. Holes 46 are provided inthe contact head 44 for rotating the spring adjusting member 38 so as tovary the position of the contact head 44 relative to the upper fusingelectrode shaft 18 and, hence, the preload compression of the spring 40.

The spring 40 is maintained in the chamber 20 by a cover plate 48removably attached to the lower fusing electrode shaft 22. The coverplate carries a firing switch 50 which cooperates with an actuating rod52, attached by a bracket 54 to the upper fusing electrode shaft 18, soas to control the actuation of a weld controller (not shown).

The lower end of the lower fusing electrode shaft 22 is removablyattached to an upper electrode holder 56, which is removably attached toa lower electrode holder 58 adapted to hold a fusing electrode 60 (seeFIG. 2). With particular reference to FIGS. 3 and 4, keyway 62 formed inthe lower electrode holder 58 receives a key 64 formed on the upperelectrode holder 56, which is provided with waterways 66 for cooling theupper electrode holder 56, as well as the lower electrode holder 58 andthe fusing electrode 60. The upper electrode holder 56 has a key 68which is received in a keyway 70 formed in the lower fusing electrodeshaft 22. The position of the fusing electrode 60 can be varied by anadjusting screw 72 threadedly received in a hole 74 which communicateswith a hole 76 adapted to receive the fusing electrode 60. A set screw78 secures the fusing electrode 60 in place in the hole 76 of the lowerelectrode holder 58. The keys 64, 68 cooperate with the keyways 62, 70,respectively, to rigidly support the fusing electrode 60 and to ensureits proper alignment and position for the successful performance of afusing operation. The key 64 and the keyway 62 also cooperate to promoteheat transfer between the upper electrode holder 56 and the lowerelectrode holder 58, thereby facilitating the cooling effect that theupper electrode holder 56 has on the lower electrode holder 58 and thefusing electrode 60.

Referring now to FIG. 6 in particular, the upper electrode holder 56 hasa pin 80 which travels between a pair of guide plates 82 attached to thehead support 12. The pin 80 and the plates 82 cooperate to prevent thefusing electrode assembly 14 from rotating about a vertical axis.

Referring again to FIGS. 1 and 2, the ground electrode assembly 16includes a ground electrode shaft 84 which is attached to the upperfusing electrode shaft 18 by the bracket 54. A collar 86, which isthreadedly attached to the upper end of the ground electrode shaft 84,cooperates which the bracket 54 to suspend the ground electrode shaft84. A flanged washer 88 is slidably received on the ground electrodeshaft 84 and resiliently urged against the lower surface of the bracket54 by a compression spring 90 interposed between the flanged washer 88and a flanged collar 92 threaded onto the ground electrode shaft 84. Theposition of the flanged collar 92 on the ground electrode shaft 84 canbe adjusted to vary the preloading compression of the spring 90. Theground electrode shaft 84 is slidably received in the upper bearingblock 24 and the lower bearing block 26.

With reference to FIG. 5 in particular, the lower end of the groundelectrode shaft 84 threadedly receives an upper end of an adjustingmember 94, the lower end of which is pinned to an insulating bushing 96.A pivot mechanism 98, which is pinned to the bushing 96, permits thepivotal movement of a support arm 100, which carries a ground electrode102 (see FIG. 2). A lock nut 104, threadedly received on the adjustingmember 94, fixes the position of the adjusting member 94 relative to theground electrode shaft 84. By loosening the nut 98 and rotating theadjusting member 94, the position of the ground electrode 102 relativeto the fusing electrode 60 can be varied quickly and easily.

As shown in FIGS. 2 and 10, the head support 12 is mounted for verticalreciprocating movement relative to a head box 106 by an elevatingassembly 108, which includes a shaft 110 and a bracket 112 adapted tothreadedly receive the shaft 110. The bracket 112 is fixedly secured tothe head box 106. The upper end of the shaft 110 extends verticallythrough a mounting block 114, which is fixedly secured to the headsupport 12, and carries a large bevel gear 116, which is pinned to theshaft 110 for rotation therewith. A small bevel gear 118 (see FIG. 10),which is pinned to a shaft 120, meshes with the large bevel gear 116.The shaft 120, which is also pinned to a manually rotatable handwheel122, extends horizontally through the mounting block 114. By rotatingthe handwheel 122, the position of the head support 12 relative to thehead box 106 can be varied to vary the position of the head support 12relative to a workpiece located below the fusing electrode 60 and theground electrode 102.

In operation, the fusing electrode 60 and the ground electrode 102 arearranged in their respective rest positions above a workpiece (notshown). When the fusing electrode 60 and the ground electrode 102 are intheir rest positions, the distance between the fusing electrode 60 andthe workpiece is slightly greater than the distance between the groundelectrode 102 and the workpiece. After the fusing electrode 60 and theground electrode 102 have assumed their rest positions, the cylinder 30is actuated, extending the piston rod 28 and thereby causing thedownward movement of the upper fusing electrode shaft 18. The springadjusting member 38 moves downward conjointly with the upper fusingelectrode shaft 18 to push the spring 40 and, hence, the lower fusingelectrode shaft 22 downward, resulting in the downward movement of theupper and lower electrode holders 56, 58 and, therefore, the fusingelectrode 60. The bracket 54 causes the ground electrode assembly 16 tomove in synchronization with the fusing electrode assembly 14.

The downward movement of the ground electrode assembly 16 causes theground electrode 102 to contact the workpiece, resulting in the furthercompression of the spring 90. The continued downward movement of thepiston rod 28 causes the fusing electrode 60 to also contact theworkpiece. Up to this stage of the operating cycle of the fusing headassembly 10, the upper fusing electrode shaft 18 and the lower fusingelectrode shaft 22 occupy the positions shown in FIG. 7.

The piston rod 28 continues its downward movement after both the fusingelectrode 60 and the ground electrode 102 have contacted the workpiece,thereby further compressing the spring 40 (see FIG. 8), as well as thespring 90, and causing the downward movement of the key 34 relative tothe slot 36 (see FIG. 8). The downward movement of the upper fusingelectrode shaft 18 is terminated when the stop 32 contacts the uppersurface of the upper bearing block 24.

As the stop 32 contacts the bearing block, the firing switch 50 isactuated to initiate a fusing operation on the workpiece. The fusingoperation causes the workpiece to heat up and melt. The spring 40 causesthe fusing electrode 60 to move downward and follow the weld, i.e., toremain in contact with the unmelted portion of the workpiece, eventhough the downward movement of the upper fusing electrode shaft 18 hasbeen arrested (see FIG. 9).

After the fusing operation is completed, the piston rod 28 is retracted,causing the key 34 to move upward relative to the slot 36. When the key34 engages the closed end of the slot 36, the continued retraction ofthe piston rod 28 causes the key 34 to pull the lower fusing electrodeshaft 22 upward conjointly with the upper fusing electrode shaft 18,thereby raising the fusing electrode 60 off of the workpiece. During theretraction of the piston rod 28, the bracket 54 contacts the collar 86so that the ground electrode assembly is moved upwardly conjointly withthe fusing electrode assembly 14, thereby raising the ground electrode102 off of the workpiece. The fusing electrode 60 and the groundelectrode 102 are automatically repositioned in their respective restpositions upon the complete retraction of the piston rod 28.

It will be understood that the embodiment described herein is merelyexemplary and that a person skilled in the art may make many variationsand modifications without departing from the spirit and scope of theinvention. All such modifications and variations are intended to beincluded within the scope of the invention as defined in the appendedclaims.

What we claim is:
 1. A fusing machine, comprising a frame; a fusingelectrode assembly mounted for reciprocating movement relative to saidframe in a first direction, in which said fusing electrode assemblymoves towards a workpiece, and a second direction opposite to said firstdirection, said fusing electrode assembly including a first fusingelectrode shaft, having an open end, a second fusing electrode shaftmounted for reciprocating movement relative to said first electrodeshaft in said open end thereof, urging means removably positioned insaid open end of said first fusing electrode shaft and interposedbetween said first fusing electrode shaft and said second fusingelectrode shaft for urging said first and second fusing electrode shaftsaway from each other, holding means attached to said first fusingelectrode shaft for holding a fusing electrode, and a stop memberadjustably attached to said second fusing electrode shaft, said stopmember cooperating with said frame in response to the reciprocatingmovement of said fusing electrode assembly in said first direction tolimit the movement of said second fusing electrode shaft in said firstdirection; and moving means for moving said fusing electrode assembly insaid first and second directions.
 2. The fusing machine according toclaim 1, further comprising permitting means for permitting radialaccess to said open end of said first fusing electrode shaft.
 3. Thefusing machine according to claim 2, wherein said permitting meansincludes a cover plate removably attached to said first fusing electrodeshaft.
 4. The fusing machine according to claim 3, wherein said coverplate carries controlling means for controlling actuation of a fusingoperation.
 5. The fusing machine according to claim 1, wherein saidframe includes a first bearing block and a second bearing block spaced afixed distance from said first bearing block, said first fusingelectrode shaft being mounted for reciprocating movement in said firstand second bearing blocks.
 6. The fusing machine according to claim 5,wherein said stop member cooperates with one of said first and secondbearing blocks to limit the movement of said second fusing electrodeshaft in said first direction.
 7. The fusing machine according to claim1, wherein said second fusing electrode shaft includes contacting meansfor contacting said first fusing electrode shaft during the movement ofsaid second fusing electrode shaft in said second direction, wherebysaid second fusing electrode shaft moves said first fusing electrodeshaft in said second direction.
 8. The fusing machine according to claim1, wherein said urging means is a compression spring.
 9. The fusingmachine according to claim 8, further comprising adjusting means carriedby said second fusing electrode shaft for adjusting the preloadcompression of said spring.
 10. The fusing machine according to claim 1,wherein said stop member is a collar threadedly received on said secondfusing electrode shaft.
 11. The fusing machine according to claim 1,wherein said moving means is a pneumatic cylinder, having a piston rodmounted for reciprocating movement into and out of said cylinder, saidpiston rod being fixedly attached to said second fusing electrode shaft.12. The fusing machine according to claim 1, wherein said holding meansincludes a first holding member, which is keyed to said first fusingelectrode shaft, and a second holding member, which is keyed to saidfirst holding member, said second holding member including firstreceiving means for removably receiving a fusing electrode and secondreceiving means, which communicates with said first receiving means, forreceiving adjusting means for adjusting the position of said fusingelectrode relative to said second holding member.
 13. The fusing machineaccording to claim 12, wherein said first holding member includeschannels which communicate with a supply of a cooling medium.
 14. Thefusing machine according to claim 12, further comprising securing meansfor releasably securing said fusing electrode in said first receivingmeans.
 15. The fusing machine according to claim 1, further comprisingpreventing means for preventing rotation of said fusing electrodeassembly about a longitudinal axis thereof.
 16. The fusing machineaccording to claim 15, wherein said preventing means includes a pinfixedly attached to said holding means and guiding means for guiding themovement of said pin relative to said frame.
 17. The fusing machineaccording to claim 1, further comprising a ground electrode assembly andsuspending means attached to said second fusing electrode shaft forsuspending said ground electrode assembly from said fusing electrodeassembly, said ground electrode assembly including a ground electrodeshaft mounted for reciprocating movement relative to said suspendingmeans in said first and second directions, biasing means for biasingsaid ground electrode shaft in said second direction, pivotablesupporting means for supporting a ground electrode adjusting meansattached to said ground electrode shaft for adjusting the position ofsaid ground electrode in said first and second directions, andpermitting means interposed between said adjusting means and saidsupporting means for permitting the pivotal movement of said supportingmeans.
 18. The fusing machine according to claim 1, further comprisingsupporting means for supporting said frame relative to a workpiece workstation and adjusting means carried by said frame for adjusting theposition of said frame relative to said supporting means.